System for generating hydrogen from a chemical hydride

ABSTRACT

An apparatus is disclosed to generate hydrogen. A liquid permeable material with one or more cavities contains a solid anhydrous chemical hydride and an anhydrous activating agent. A housing that is heat and pressure resistant houses the liquid permeable material, and a liquid. One or more liquid sources inject the liquid into the housing such that the liquid contacts at least a portion of the liquid permeable material. A gas outlet port releases hydrogen gas produced by a reaction comprising the solid anhydrous chemical hydride, the anhydrous activating agent, and the liquid. A hydrogen output regulator controls the amount of hydrogen gas that the gas outlet port releases.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 60/820,574 entitled “APPARATUS, SYSTEM, AND METHOD FORGENERATING ELECTRICITY FROM A CHEMICAL HYDRIDE” and filed on Jul. 27,2006 for Kevin Shurtleff, et. al which is incorporated herein byreference. This application incorporates by reference U.S. Pat. Nos.7,393,369 filed Jun. 11, 2003, U.S. Pat. No. 7,438,732 filed Nov. 12,2005, U.S. patent application Ser. Nos. 11/740,349 filed Apr. 26, 2007,and U.S. patent application Ser. No. 11/828,265 filed Jul. 25, 2007; andU.S. Provisional Patent Applications Ser. No. 60/820,574 filed Jul. 27,2006, 60/951,903 filed Jul. 25, 2007, 60/951,907 filed Jul. 25, 2007,and 60/951,925 filed Jul. 25, 2007, each of which is incorporated byreference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to hydrogen generation and more particularlyrelates to hydrogen generation from a chemical hydride.

2. Description of the Related Art

As the cost of fossil fuels increases, pollution increases, and theworldwide supply of fossil fuels decreases, alternative energy sourcesare becoming increasingly important. Hydrogen is a plentiful alternativeenergy source, but it generally exists in a combination with otherelements, and not in a pure form. The additional elements add mass andmay prevent the hydrogen from being used as an energy source. Purehydrogen, however, is a desirable energy source. Pure hydrogen comprisesfree hydrogen atoms, or molecules comprising only hydrogen atoms.Producing pure hydrogen using conventional methods is generally costprohibitive.

One way that pure hydrogen can be generated is by a chemical reactionwhich produces hydrogen molecules. The chemical reaction that occursbetween water (H₂O) and chemical hydrides produces pure hydrogen.Chemical hydrides are molecules comprising hydrogen and one or morealkali or alkali-earth metals. Examples of chemical hydrides includelithium hydride (LiH), lithium tetrahydridoaluminate (LiAlH₄), lithiumtetrahydridoborate (LiBH₄), sodium hydride (NaH), sodiumtetrahydridoaluminate (NaAlH₄), sodium tetrahydridoborate (NaBH₄), andthe like. Chemical hydrides produce large quantities of pure hydrogenwhen reacted with water, as shown in reaction 1.NaBH₄+2H₂O→NaBO₂+4H₂   (1)

Recently, the interest in hydrogen generation has increased, because ofthe development of lightweight, compact Proton Exchange Membrane (PEM)fuel cells. One by-product of generating electricity with a PEM fuelcell is water, which can be used or reused to produce pure hydrogen fromchemical hydrides for fuelling the PEM fuel cell. The combination of PEMfuel cells with a chemical hydride hydrogen generator offers advantagesover other energy storage devices in terms of gravimetric and volumetricenergy density.

Unfortunately, the prior art has encountered unresolved problemsproducing pure hydrogen from chemical water/hydride reactions.Specifically, conventional systems, methods, and apparatuses have notsuccessfully controlled the chemical reaction between the water and thechemical hydride without adversely affecting the gravimetric andvolumetric energy density of the overall system.

The chemical reaction between water and a chemical hydride is verysevere and highly exothermic. The combination of water and a chemicalhydride must be precisely controlled to prevent a runaway reaction or anexplosion. Many failed attempts have been made to properly control thereaction while still preserving the gravimetric and volumetric energydensity provided by the chemical hydrides

One attempt to properly control the reaction involves separating waterfrom the chemical hydride using a membrane. Generally, the membranepasses water because of a difference in water pressure across themembrane. Water pressure on the side of the membrane opposite thechemical hydride pushes water through the membrane, because water isquickly used up in the reaction with the chemical hydride. Othermembranes utilize a capillary action to transport water from one side ofthe membrane to the other. Consequently, a water supply must be providedthat supplies water to the water side of the membrane to be transportedby capillary action to the chemical hydride side of the membrane.

One side effect of such a system is that the chemical hydride will “gum”or “clump” as water is introduced. Gumming or clumping refers to thespheres or other geometric shapes formed by the chemical hydride and itsbyproducts during the reaction. Water is able to react with the outerportion of the “clump” to a certain depth, however, large portions ofthe “clump” remain unreacted because water cannot penetrate deeplyenough into the “clump.” Consequently, the gravimetric and volumetricenergy density is decreased because of the large percentage of thechemical hydride that remains unreacted. This is inefficient andunacceptable.

Accordingly, what is needed is an improved apparatus that overcomes theproblems and disadvantages of the prior art. The apparatus shouldpromote a substantially complete and controlled reaction of an anhydroushydride reactant. In particular, the apparatus should control a chemicalreaction between water and a chemical hydride without relying on a waterpressure differential across a membrane.

SUMMARY OF THE INVENTION

The present invention has been developed in response to the presentstate of the art, and in particular, in response to the problems andneeds in the art that have not yet been fully solved by currentlyavailable hydrogen generation systems. Accordingly, the presentinvention has been developed to provide an apparatus for generatinghydrogen from a chemical hydride that overcome many or all of theabove-discussed shortcomings in the art.

The apparatus to generate hydrogen is provided with a plurality ofmodules configured to functionally execute the necessary steps ofhydrogen production from a chemical hydride. These modules in thedescribed embodiments include a liquid permeable material, a housing,one or more liquid sources, a gas outlet port, a hydrogen outputregulator, a liquid reservoir, one or more pumps, a liner, a crimp, anend cap, an activated charcoal filter, one or more housing alignmentfeatures, and an O-ring.

In one embodiment, the liquid permeable material has one or morecavities, each cavity containing a solid anhydrous chemical hydride andan anhydrous activating agent. The cavities, in one embodiment, are oneor more tubular pouches in a side-by-side configuration. In anotherembodiment, the tubular pouches are rolled such that a longitudinal axisof the rolled one or more tubular pouches oriented coaxial with alongitudinal axis of the housing

In a further embodiment, the housing comprises a heat and pressureresistant material. The housing receives the liquid permeable material,and a liquid. In one embodiment, the housing has a crimp thatcircumscribes the end cap that is seated within a housing opening. Thecrimp releases the hydrogen gas in response to a gas pressure above apredetermined gas pressure. The housing, in one embodiment, has anactivated charcoal filter that absorbs impurities from hydrogen gasexiting the housing. In a further embodiment, the housing iscylindrical.

In another embodiment, the one or more liquid sources inject the liquidinto the housing such that the liquid contacts at least a portion of theliquid permeable material. In one embodiment, the liquid compriseswater. In one embodiment, the liquid sources comprise one or more liquidconduits disposed within the housing.

The gas outlet port, in one embodiment, releases hydrogen gas producedby a reaction between the solid anhydrous chemical hydride, theanhydrous activating agent, and the liquid. In one embodiment, thehydrogen output regulator controls the amount of hydrogen gas that thegas outlet port releases. In another embodiment, the hydrogen outputregulator comprises a check valve that allows the hydrogen gas to exitthe gas outlet port, but prevents the hydrogen gas from entering the gasoutlet port. In a further embodiment, the hydrogen output regulatorregulates a gas pressure of the hydrogen gas that the gas outlet portreleases such that the gas pressure remains at or below a predeterminedgas pressure. In one embodiment, the one or more liquid sources comprisea liquid reservoir and one or more pumps, each of the one or more pumpsconfigured to pump liquid from the liquid reservoir into the housing ata liquid injection rate. In another embodiment, the hydrogen outputregulator comprises a controller that manages the liquid injection rate.

In another embodiment, the liner is disposed between the housing and theliquid permeable material. The liner protects the housing from corrosionand damage.

The housing alignment features, in one embodiment, ensure that thehousing is disposed in a predetermined position and alignment relativeto one or more receiving alignment features of an apparatus receiver. Inanother embodiment, the one or more housing alignment features comprisea handle. In a further embodiment, the one or more housing alignmentfeatures engage the gas outlet port. In one embodiment, the O-ringcircumscribes the gas outlet port to produce a seal between the gasoutlet port and a receiver gas port. The O-ring breaks the seal andreleases the hydrogen gas in response to a gas pressure above apredetermined gas pressure.

A system of the present invention is also presented to generatehydrogen. The system may be embodied by a fuel cartridge, a cartridgeinterface, and a fuel cartridge receiver. In particular, the fuelcartridge, in one embodiment, includes a liquid permeable material, ahousing, and one or more liquid sources.

The system may further include a cartridge cooling module, a condenser,one or more alignment sensors, one or more temperature sensors, one ormore pressure sensors, a state of fill module, a radio frequencyidentification tag, a bar code, a memory, a liquid reservoir, and one ormore pumps.

Another apparatus of the present invention is also presented to generatehydrogen. The apparatus in the disclosed embodiments substantiallyincludes the elements presented above with respect to the operation ofthe described apparatus and system.

Reference throughout this specification to features, advantages, orsimilar language does not imply that all of the features and advantagesthat may be realized with the present invention should be or are in anysingle embodiment of the invention. Rather, language referring to thefeatures and advantages is understood to mean that a specific feature,advantage, or characteristic described in connection with an embodimentis included in at least one embodiment of the present invention. Thus,discussion of the features and advantages, and similar language,throughout this specification may, but do not necessarily, refer to thesame embodiment.

Furthermore, the described features, advantages, and characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. One skilled in the relevant art will recognize that theinvention may be practiced without one or more of the specific featuresor advantages of a particular embodiment. In other instances, additionalfeatures and advantages may be recognized in certain embodiments thatmay not be present in all embodiments of the invention.

These features and advantages of the present invention will become morefully apparent from the following description and appended claims, ormay be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are nottherefore to be considered to be limiting of its scope, the inventionwill be described and explained with additional specificity and detailthrough the use of the accompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of asystem for generating electricity from a chemical hydride in accordancewith the present invention;

FIG. 2A is a schematic block diagram illustrating one embodiment of ahydrogen fuel cartridge in accordance with the present invention;

FIG. 2B is a schematic block diagram illustrating another embodiment ofa hydrogen fuel cartridge in accordance with the present invention;

FIG. 3A is a schematic block diagram illustrating a further embodimentof a hydrogen fuel cartridge in accordance with the present invention;

FIG. 3B is a schematic block diagram illustrating one embodiment of aliquid permeable material in accordance with the present invention;

FIG. 4A is a schematic block diagram of one embodiment of a hydrogengeneration system interface in accordance with the present invention;

FIG. 4B is a schematic block diagram of one embodiment of a hydrogengeneration system interface in accordance with the present invention;

FIG. 5 is a schematic block diagram of one embodiment of a coolingsystem for a hydrogen generation system in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Many of the functional units described in this specification have beenlabeled as modules, in order to more particularly emphasize theirimplementation independence. For example, a module may be implemented asa hardware circuit comprising custom VLSI circuits or gate arrays,off-the-shelf semiconductors such as logic chips, transistors, or otherdiscrete components. A module may also be implemented in programmablehardware devices such as field programmable gate arrays, programmablearray logic, programmable logic devices or the like.

Modules may also be implemented in software for execution by varioustypes of processors. An identified module of executable code may, forinstance, comprise one or more physical or logical blocks of computerinstructions which may, for instance, be organized as an object,procedure, or function. Nevertheless, the executables of an identifiedmodule need not be physically located together, but may comprisedisparate instructions stored in different locations which, when joinedlogically together, comprise the module and achieve the stated purposefor the module.

Indeed, a module of executable code may be a single instruction, or manyinstructions, and may even be distributed over several different codesegments, among different programs, and across several memory devices.Similarly, operational data may be identified and illustrated hereinwithin modules, and may be embodied in any suitable form and organizedwithin any suitable type of data structure. The operational data may becollected as a single data set, or may be distributed over differentlocations including over different storage devices, and may exist, atleast partially, merely as electronic signals on a system or network.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention. Thus,appearances of the phrases “in one embodiment,” “in an embodiment,” andsimilar language throughout this specification may, but do notnecessarily, all refer to the same embodiment.

Reference to a signal bearing medium may take any form capable ofgenerating a signal, causing a signal to be generated, or causingexecution of a program of machine-readable instructions on a digitalprocessing apparatus. A signal bearing medium may be embodied by atransmission line, a compact disk, digital-video disk, a magnetic tape,a Bernoulli drive, a magnetic disk, a punch card, flash memory,integrated circuits, or other digital processing apparatus memorydevice.

Furthermore, the described features, structures, or characteristics ofthe invention may be combined in any suitable manner in one or moreembodiments. In the following description, numerous specific details areprovided, such as examples of programming, software modules, userselections, network transactions, database queries, database structures,hardware modules, hardware circuits, hardware chips, etc., to provide athorough understanding of embodiments of the invention. One skilled inthe relevant art will recognize, however, that the invention may bepracticed without one or more of the specific details, or with othermethods, components, materials, and so forth. In other instances,well-known structures, materials, or operations are not shown ordescribed in detail to avoid obscuring aspects of the invention.

FIG. 1 depicts one embodiment of a system 100 for generating electricityfrom a chemical hydride in accordance with the present invention. Thesystem 100 includes a hydrogen generation system 101, a hydrogenconsuming device 102, an electrical and control system 103, and an outerhousing 104.

In one embodiment, the hydrogen generation system 101 includes one ormore cartridge receivers 105, one or more hydrogen fuel cartridges 106,a housing lid 107, one or more locking and alignment structures 108, ahandle 109, a liquid permeable material 110, one or more liquidinjection lines and tubes 111, one or more cooling modules 112, one ormore hydrogen ports 114, an activated charcoal filter 116, a temperaturesensor 118, a cartridge sensor 120, a radio frequency identification(RFID) tag 122, an RFID sensor 124, a pump 126, a liquid reservoir 128,a level sensor 129, a check valve 130, a hydrogen pressure sensor 132,one or more mechanical valves 133, a water trap 134, a transfer valve136, a condenser 138, and an air pressure control valve 140. In general,the hydrogen generation system 101 generates hydrogen using a liquidsuch as water, a chemical hydride, and an activating agent.

In one embodiment, the cartridge receiver 105 comprises a durablematerial that can withstand high temperatures associated with hydrogengeneration. In a further embodiment, the cartridge receiver 105 alsocomprises a lightweight material, to keep the overall weight of thesystem 100 to a minimum for added portability. In one embodiment, thecartridge receiver 105 is a lightweight metal or metal alloy such asaluminum or the like. In a further embodiment, the cartridge receiver105 comprises a fiberglass material, a plastic polymer material, aceramic material, or another durable material. In one embodiment, thecartridge receiver 105 also comprises a housing lid 107 and otherstructures configured to receive, align, and lock the hydrogen fuelcartridge 106.

In one embodiment, the hydrogen fuel cartridge 106 locks into thecartridge receiver 105. The hydrogen fuel cartridge 106 is discussed ingreater detail with reference to FIG. 2. In general, the hydrogen fuelcartridge 106 is configured to house a chemical hydride and anactivating agent, to receive a liquid such as water, to house a chemicalreaction between the chemical hydride and the liquid which produceshydrogen gas, and to release the hydrogen gas.

In one embodiment, the hydrogen fuel cartridge 106 is cylindrical inshape. The cylindrical shape provides structural strength to withstandthe internal pressures as hydrogen is produced. The hydrogen fuelcartridge 106 may comprise a material configured to withstand the heatand pressure of the chemical reaction. The material may also comprise alightweight material selected to minimize the weight of the hydrogenfuel cartridge 106, such as a lightweight metal or metal alloy likealuminum, a plastic polymer, or other durable material. In anotherembodiment, the hydrogen fuel cartridge 106 comprises a stamped aluminumcylindrical cartridge.

In another embodiment, the hydrogen fuel cartridge 106 comprises aremovable and/or disposable material such as a flexible plastic polymerthat may be substantially similar to the liner discussed below, and thecartridge receiver 105 may comprise a more durable outer housingcomprising a metal or metal alloy, a ceramic, a rigid plastic polymer orthe like. The durable outer housing may include a screw on cap thatsecures the removable and/or disposable hydrogen fuel cartridge 106.

The housing lid 107, in one embodiment, closes to secure the hydrogenfuel cartridge 106 in the cartridge housing 105. In another embodiment,the housing lid 107 may act as a backup securing system for the hydrogencartridge 106. For example, the hydrogen fuel cartridge 106 may besecured to the cartridge housing 105 by a securing mechanism (notshown), and the housing lid 107 may close on the installed hydrogen fuelcartridge 106 to provide added security in the event of a failure of thesecuring mechanism (not shown).

In another embodiment, the housing lid 107 locks and aligns the hydrogenfuel cartridge 106. The housing lid 107 may have various structuresformed thereon and within for mating with the hydrogen fuel cartridge106. Within the housing lid 107 may be alignment structures, guideblocks, guide pins, or the like which may mate with correspondingalignment structures 108 on the hydrogen fuel cartridge 106. In anotherembodiment, the cartridge receiver 105 may include alignment structures,guide blocks, guide pins, or the like which may mate with correspondingalignment structures 108 on the hydrogen fuel cartridge 106.Additionally, the housing lid 107 may include one or more portconnectors configured to mate with one or more liquid conduits 111, andone or more hydrogen ports 114.

In one embodiment, indentions around port connectors in the housing lid107 will accommodate sealing devices such as O-rings or gaskets. In oneembodiment, lines, manifolds, tubing or the like may be in fluidcommunication with one or more liquid passages in the housing lid 107and with a liquid source, and thereby provide fluid communicationthrough the housing lid 107 to one or more liquid ports 108 on thehydrogen fuel cartridge 106. In certain embodiments, the lines,manifolds, tubing or the like are coupled to another manifold (notshown) that distributes the liquid to the housing lid 107. In oneembodiment, the housing lid 107 will include internal liquid passages.In another embodiment, the cartridge receiver 105 may comprise one ormore lines, manifolds, tubes and the like in fluid communication withone or more liquid passages in the housing lid 107 and with a liquidsource.

In one embodiment, the hydrogen generation system 101 includes alignmentstructures 108, a shoulder, guide blocks, guide pins, or the like whichmay mate with corresponding alignment structures 108 on the hydrogenfuel cartridge 106. In another embodiment, the cartridge housing 105 mayinclude alignment structures 108, guide blocks, guide pins, or the likewhich may mate with corresponding alignment structures 108 on thehydrogen fuel cartridge 106.

In one embodiment, the top of the hydrogen fuel cartridge 106 has one ormore locking and alignment structures 108. In one embodiment, the one ormore locking and alignment structures 108 are configured to engage oneor more corresponding locking and alignment structures 108 of thecartridge receiver 105. The locking and alignment structures 108 of thecartridge receiver 105 may be a shoulder, guide blocks, pins, bolts,screws, keys, or the like. In one embodiment, the locking and alignmentstructures 108 comprise a threaded hole and a non-threaded hole. In oneembodiment the threaded hole is configured to accept a bolt or screwattached to a handle on the top lid of the cartridge housing 105. In oneembodiment, a bolt, screw, or quarter turn lock in the housing lid 107locks into a threaded or ramped hole 108 in the hydrogen fuel cartridge106 with a quarter turn of the handle.

Advantageously, the locking and alignment structures 108 provide forquick and safe installation of a fresh hydrogen fuel cartridge 106. Inone embodiment, the hydrogen fuel cartridge 106 is oriented verticallywith respect to the outer housing 104. In this manner, a user mayquickly remove a used hydrogen fuel cartridge 106 and insert a freshhydrogen fuel cartridge 106. In a further embodiment, the hydrogen fuelcartridge 106 is oriented horizontally with respect to the outer housing104. The locking and alignment structures 108 ensure that inlet ports ofthe hydrogen fuel cartridge 106 line up and seal properly. In oneembodiment, improper positioning of the hydrogen fuel cartridge 106causes the cartridge 106 to extend beyond the cartridge receiver 105.Consequently, the housing lid 107 will not close. The user may then spinthe hydrogen fuel cartridge 106 about its center axis until the lockingand alignment structures 108 align and the hydrogen fuel cartridge 106properly seats within the cartridge receiver 105.

In one embodiment, a top portion of the hydrogen fuel cartridge 106 hasa handle 109. The handle 109 may comprise a durable plastic, metal, orother material. In one embodiment, the handle 109 is configured to pivotalong a 90 degree arc, between a position perpendicular to the top ofthe hydrogen fuel cartridge 106, and a position parallel to the top ofthe hydrogen fuel cartridge 106.

The handle 109 may also serve as a locking and alignment structure 108.In such an embodiment, the handle 109 fits into a corresponding space inthe cartridge receiver 105 and/or the housing lid 107 of the cartridgehousing 105 only when the hydrogen fuel cartridge 106 is properlypositioned about its center vertical axis and the handle 109 ispositioned within the plane of the top of the hydrogen fuel cartridge106. In this position, the handle 109 allows the housing lid 107 toclose and lock. The handle 109 restricts the rotation of the hydrogenfuel cartridge 106 and ensures a proper alignment of the hydrogen fuelcartridge 106 within the cartridge housing 105.

In one embodiment, the chemical hydride and the activating agent arestored in a liquid permeable material 110 within the hydrogen fuelcartridge 106. The liquid permeable material 110 is discussed in greaterdetail with reference to FIGS. 3A and 3B. In general, the liquidpermeable material 110 comprises a material configured to distribute aliquid evenly, without retaining a significant amount of the liquid. Ina further embodiment, the liquid permeable material 110 is furtherconfigured with one or more sections, pouches, or cavities, eachsection, pouch, or cavity configured to hold and to evenly distribute apredetermined amount of the chemical hydride and the activating agent.The liquid permeable material 110 may be rolled as illustrated in FIG.1, or may be in multiple rolls, folds, stacks, or other configurations.In one embodiment, the hydrogen fuel cartridge 106 includes a pluralityof liquid permeable materials 110, each rolled as illustrated in FIG. 1,and distributed about a central longitudinal axis of the hydrogen fuelcartridge 106, with a central rolled liquid permeable material 110centered about the central longitudinal axis of the hydrogen fuelcartridge 106.

In one embodiment, a liquid such as water enters the hydrogen fuelcartridge 106 through one or more liquid conduits 111. The liquidconduits 111 may comprise tubes, integrated passages, ports, and thelike. As described above, in one embodiment the liquid conduits 111 maybe removably coupled to the housing lid 107 with an O-ring or similarseal, and the housing lid 107 may be coupled to the pump 126 by one ormore lines, manifolds, tubes and the like. In another embodiment, theliquid conduits 111 may be removably coupled to the housing lid 107 withan O-ring or similar seal, and the housing lid 107 may be coupled to thepump 126 by one or more lines, manifolds, tubes and the like. The liquidconduits 111 may be configured to disperse a liquid such as water withinthe liquid permeable material 110, such that the liquid and the chemicalhydride react to release hydrogen gas.

In one embodiment, the cartridge 106 is oriented vertically, and theliquid conduits 111 are configured to fill the cartridge 106 with aliquid such as water from the bottom of the cartridge 106. In a furtherembodiment, the cartridge 106 is oriented horizontally, and the liquidconduits 111 are configured to evenly disperse a liquid such as water inthe horizontal cartridge 106. In one embodiment, the hydrogen fuelcartridge 106 may comprise a plurality of liquid conduits 111. Inanother embodiment, the hydrogen fuel cartridge 106 includes one or moreswitching valves allowing a liquid such as water to be selectivelyinjected through one or more of the liquid conduits 111 and not throughother of the liquid conduits 111.

In one embodiment, the liquid conduits 111, the pump 126, and/or theliquid reservoir 128 comprise a liquid source. In another embodiment,the liquid conduits 111 may be coupled to another liquid source, such asa municipal water source, a pressurized water tank, a liquid reservoirintegrated with the cartridge 106, and/or another liquid source. Asdiscussed below with regards to FIG. 3, the liquid may comprise water, awater soluble activating agent mixed with water, an aqueous substancesuch as hydrochloric acid (HCl), or the like.

In one embodiment, the cooling module 112 is coupled to the cartridgereceiver 105. The cooling module is discussed in greater detail withregards to FIG. 4. In general, the cooling module 112 is configured todisperse the heat produced by the chemical reaction between a liquidsuch as water and the chemical hydride. In one embodiment, the coolingmodule 112 includes low power fans that provide high airflows. In afurther embodiment, the electrical and control system 103 may adjust theairflow from the cooling module 112 according to the temperature of thefuel cartridge 106 as measured by the temperature sensor 118 to reduceparasitic power losses.

In another embodiment, the cooling module 112 comprises one or moreblowers that are not affected by backpressure within the cartridgereceiver 105. The one or more blowers may be configured to maintain ahigher air pressure than an axial fan. One or 4more forms, guides,manifolds, or heat dams may be used to control and direct the flow ofair around the fuel cartridge 106. In a further embodiment, the coolingmodule 112 may comprise a water pump configured to pump water around thecartridge 106 to facilitate a heat transfer between the cartridge andthe water. The water pump may pump the water through tubing, pipes,passages, manifolds, or through channels in the cartridge receiver 105or the cartridge 106. A heat sink comprising a metal, graphite, or otherthermally conductive material may also be used.

In one embodiment, one or more hydrogen ports 114 are integrated withthe alignment structures 108 on the hydrogen fuel cartridge 106. In afurther embodiment, the hydrogen ports 114 are in fluid communicationwith one or more port connectors in the cartridge receiver 105. Thehydrogen port connectors in the cartridge receiver 105 may include sealsor O-rings. The hydrogen ports 114 may comprise one or more interfacegas outlet ports in a cartridge interface that are configured to matewith one or more receiver gas ports in the cartridge receiver 105. Theseals or O-rings may substantially circumscribe the hydrogen ports 114,to produce a seal between each of the one or more hydrogen ports 114 andthe one or more receiver gas ports in the cartridge receiver 105. Inanother embodiment, the O-rings are configured to break the seal andrelease the hydrogen gas in response to a gas pressure above apredetermined safe hydrogen gas pressure. This ensures that the hydrogengeneration system 101 remains a safe, low pressure system.

In one embodiment, hydrogen gas exiting the inside of the hydrogen fuelcartridge 106 passes through an activated charcoal filter 116. In oneembodiment, the activated charcoal filter 116 is integrated with thehydrogen fuel cartridge 106. In this manner, the activated charcoalfilter 116 is replaced when the hydrogen fuel cartridge 106 is replaced.The activated charcoal filter 116, in one embodiment is located near thetop of the hydrogen fuel cartridge 106 between the hydrogen ports 114and the liquid permeable material 108. In another embodiment, theactivated charcoal filter 116 is located external to, and downstream of,the hydrogen fuel cartridge 106. The activated charcoal filter 116 isconfigured to remove impurities such as hydrocarbons, other organiccompounds, water vapor, dissolved or solid salts, or other impuritiesfrom the generated hydrogen gas. The activated charcoal filter 116 maycomprise activated carbon such as charcoal, and/or other individualfilters, condensers, or coalescers comprising material suitable forfiltering impurities from hydrogen gas. The activated charcoal filter116 may also comprise a particulate filter configured to removeparticles greater than a predefined size from the hydrogen gas. In oneembodiment, the predefined size is about 5 microns. The activatedcharcoal filter 116 may be integrated with the fuel cartridge 106.

In one embodiment, the temperature sensor 118 is configured to monitorthe temperature of the hydrogen fuel cartridge 106 and the cartridgereceiver 105. The temperature sensor 118 may make contact with, bedisposed within, or otherwise read the temperature of the cartridgereceiver 105 and/or the fuel cartridge 106. The temperature that thetemperature sensor 118 reads may cause the electrical and control system103 to activate or deactivate the cooling module 112 or adjust othersystem variables to meet predetermined safety and usability standards.

In one embodiment, one or more cartridge sensors 120 determine thepresence or absence of the hydrogen fuel cartridge 106. In a furtherembodiment, the cartridge sensors 120 may comprise one or more alignmentsensors that determine whether the hydrogen fuel cartridge 106 isproperly aligned for operation. The cartridge sensors 120 may be one ormore manual switches, optical sensors, magnetic sensors, or other typesof sensors capable of determining when the fuel cartridge 106 ispresent. Preferably, the cartridge sensors 120 are optical sensors.Optical cartridge sensors 120 are easier to position and calibrateduring the manufacturing process and provide precise measurementswithout wearing overtime as may occur with mechanical switches. In afurther embodiment, the cartridge sensors 120 are also configured todetermine when the housing lid 107 is properly closed and locked. Thecartridge sensors 120 may comprise multiple cartridge sensors in variouspositions in or around the hydrogen fuel cartridge 106, the cartridgereceiver 105, and the housing lid 107.

In one embodiment, the system 100 is configured to prevent hydrogenproduction unless one or more system sensors determine that the system100 is in a proper system state. The one or more system sensors may beselected from the group consisting of the temperature sensors 118, 164,the cartridge sensor 120, the hydrogen pressures sensors 132, 144, andother system state sensors. In one embodiment, the system 100 preventshydrogen production until the housing lid 107 is detected as properlyclosed and locked, and the cartridge 106 is detected as present. In afurther embodiment, the system 100 is configured to prevent the housinglid 107 from unlocking or opening until the temperature of the hydrogenfuel cartridge 106, as measured by the temperature sensor 118, is withina safe handling range, to prevent injury to the user. In a furtherembodiment, the system 100 is configured to prevent the housing lid 107from unlocking or opening until the flow of hydrogen has dropped below acertain flow rate or the gas pressure of the hydrogen fuel cartridge106, as measured by the pressure sensor 132, is within a safe range, toprevent risk to the user. In one embodiment, the electrical and controlsystem 103 controls the hydrogen production based on inputs from one ormore system sensors. In a further embodiment, the electrical and controlsystem 103 controls a system controlled lock on the housing lid 107based on inputs from the cartridge temperature sensor 118.

In one embodiment, the hydrogen fuel cartridge 106 includes an RFID tag122 or other identifying device, such as a barcode. The RFID tag 122,barcode, or other identifying device may be embedded in, mounted on, orotherwise coupled to the hydrogen fuel cartridge 106 such that it isreadable and/or writeable by the ID sensor 124 coupled to the cartridgereceiver 105. In a further embodiment, the RFID tag 122 includes aunique cartridge identifier, such as an identification number. Byuniquely identifying each cartridge 106, the system 100 may provideusage statistics to the user, including alerts when the cartridge 106 islow on fuel and when the cartridge 106 must be replaced, even when thecartridge 106 is removed from the system 100 prior to exhaustion andlater returned to the system 100.

In one embodiment, the electrical and control system 103 may comprise astate of fill module 194 that is configured to store usage informationfor one or more hydrogen fuel cartridges 106 corresponding to the uniquecartridge identification number associated with each hydrogen fuelcartridge 106. For example, the state of fill module 194 may comprise amemory, where the state of fill module 194 may store the usageinformation. In another embodiment, the RFID tag 122 comprises a memory,and is readable and writeable, and the state of fill module 194 maywrite usage information to the RFID tag 122, using the ID sensor 124 orthe like. By storing usage information on the RFID tag, the state offill module 194 has valid usage information, even when the cartridge 106is used in multiple systems. The state of fill module 194 may collectusage information, including the amount of fuel remaining in thecartridge 106, by monitoring the amount of a liquid such as waterinjected into the cartridge 106, or by monitoring the amount of hydrogenthat has exited the cartridge 106. Because the amount of reactantswithin the cartridge 106 is known, and the amount of reactant used witheach pulse of liquid injected is known, the state of fill module 194 mayuse a simple chemical reaction calculation to determine an estimate ofhow much hydride reactant has been used, how much hydride reactantremains, and how much hydrogen gas is producible by the fuel cartridge106. In one embodiment, the electrical and control system 103 adjustsone or more system control parameters based on the usage informationthat the state of fill module 194 calculates corresponding to aparticular fuel cartridge 106.

In one embodiment, a liquid is pumped into the hydrogen fuel cartridge106 through the one or more liquid conduits 111 by the pump 126. In oneembodiment, the pump 126 is configured to pump the liquid in discretepulses, according to a dynamic pulse rate or liquid injection rate thatthe controller 192 determines based on the hydrogen production orhydrogen pressure and the power demanded by an electric load coupled tothe system 100. Pumping the liquid at variable pulse rates provides veryfine control over the amount of the liquid supplied.

In one embodiment, the controller 192 employs an algorithm to determineliquid injection rate. In such an embodiment, the controller 192receives input regarding the demand from the electric load, the demandfor electricity from the system itself (also known as the balance ofplant or “BOP”), the electricity output of the fuel cell 146 (or fuelcell stack), the pressure of produced hydrogen that has not yet beensent to the fuel cell 146, and the current charge level of the one ormore power storage devices 168. The controller 192 then sets the liquidinjection rate at a level that optimizes the use of the hydrogen thatwill be produced from the cartridge 106 by accommodating a productiondelay that is inherent generation of hydrogen from a hydride. Theproduction delay is a time delay between when the liquid injection rateis changed and when the resulting change in the hydrogen production rateoccurs. Various algorithms may be used to determine the optimal liquidinjection rate.

The controller 192 may determine the total wattage desired from the fuelcell 146 for the next cycle in the future (a cycle is the time betweenwhen the controller 192 determines whether or not to make an adjustmentto the liquid injection rate and potentially make such an adjustment).Next, the controller 192 determines whether the one or more powerstorage devices 168 are charged above, below, or at a desired chargelevel. Preferably, the desired charge level is less than full charge forexample about 80%. With such a desired charge level, the controller 192is capable of and may divert excess electricity from the fuel cell tothe one or more power storage devices 168 and the excess electricitywill not be wasted. Similarly, excess hydrogen produced due to theproduction delay can be converted by the fuel cell 146 into electricityrather than being wasted (i.e. the pressure exceeds a safety level andmust be purged).

The controller 192 also determines whether the pressure of producedhydrogen that has not yet been sent to the fuel cell 146 is within anacceptable range. Too high of a pressure may cause safety concerns thattrigger purging of the excess hydrogen by the controller 192 or othersafety devices. Too little hydrogen pressure may exacerbate theproduction delay.

The controller 192 then defines a liquid injection rate that willincrease hydrogen production such that the pressure of produced hydrogenthat has not yet been sent to the fuel cell 146 will come within theacceptable range (either increasing or decreasing) and the totalelectric power demand, from the electric load and the BOP is met eitherfrom the fuel cell 146 or from the one or more power storage devices168. In addition, the controller 192 may define the liquid injectionrate such that electricity from the fuel cell 146 that is not needed forthe electric load or BOP may be used to recharge the one or more powerstorage devices 168 back to the desired charge level.

In certain embodiments, the controller 192 adjusts the liquid injectionrate and an electricity production rate of the fuel cell 146 in responseto the inputs described above in relation to the liquid injection rate.Adjusting the electricity production rate of the fuel cell 146 maycomprise increasing the flow rate of oxygen or air passing through thefuel cell 146.

In one embodiment, the controller 192 determines the pulse rate usingone or more mathematical or statistical curves. In a further embodiment,the controller 192 determines the pulse rate using a hydrogen pressurecurve, and an electrical power demand curve, each curve havingindividual slopes and magnitudes. In one embodiment, the magnitudes atvarying points along the curves signify an amount of time betweenpulses. The magnitudes may be positive or negative, with positive valuessignifying a slower pulse rate, and negative values signifying a fasterpulse rate. When the controller 192 uses multiple curves, the controller192 may add the magnitudes from each curve at the point on the curvecorresponding to a current system state together to determine the pulserate.

The pump 126 is a pump capable of pumping a liquid into the fuelcartridge 106 through the one or more liquid conduits 111. In oneembodiment, the pump 126 is a peristaltic pump. Use of a peristalticpump is advantageous because a peristaltic pump cannot contaminate theliquid that it pumps, is inexpensive to manufacture, and pumps aconsistent, discrete amount of liquid in each pulse. Advantageously, aperistaltic pump provides a consistent and discrete amount of liquidregardless of the backpressure in the liquid in the liquid conduits 111.

In one embodiment, the controller 192 determines the amount of hydrogengas produced, and the potential amount of hydrogen production remainingin the fuel cartridge 106 by tracking the number of pulses made by thepump 126. The controller 192 may determine the remaining hydrogenpotential of the fuel cartridge 106 based on the amount of chemicalhydride originally in the fuel cartridge 106, the size of each pulsethat the pump 126 pumps, and the number of pulses that the pump 126 haspumped. The controller 192 may define the pump 126 pulse quantity orliquid injection rate based on the hydrogen gas requirements of the fuelcell 146, which are based on the electric power demands of the system100 and one or more electric loads coupled to the system 100. In oneembodiment, the pump 126 pulse quantity is between about 75 μL to 100μL. In addition, a peristaltic pump 126 allows the control system 103 toreverse the direction of the pump to withdraw the liquid from thecartridge 106 and thereby slow the production of hydrogen. This finedegree of control allows the production of hydrogen to more closelymatch the demands of the hydrogen consuming device 102.

The pump 126 pumps a liquid that is stored in the liquid reservoir 128.In a further embodiment, the liquid reservoir 128 is configured to storewater that is recycled by the system 100. To recycle water, water isremoved from the hydrogen exiting the hydrogen fuel cartridge 106 andreturned to the liquid reservoir 128, as described below in relation tothe water trap 134. The flow of moist air and hydrogen exiting the fuelcell stack 146 may also be pumped, guided, or forced into the liquidreservoir 128, and forced through the condenser 138 as described below.In another embodiment, a user may add liquid to the liquid reservoir 128manually. In a further embodiment, the liquid reservoir 128 may compriseanother liquid source, such as a municipal water source, a groundwaterwell, or the like. In another embodiment, the liquid reservoir 128 maybe coupled to or integrated with the fuel cartridge 106.

In one embodiment, the liquid level detector 129 monitors a liquid orwater level of the liquid reservoir 128. The liquid level detector 129may be an ultrasonic sensor, a float sensor, a magnetic sensor,pneumatic sensor, a conductive sensor, a capacitance sensor, a pointlevel sensor, a laser sensor, an optical sensor, or another water levelsensor. In a further embodiment, the liquid level detector 129 comprisesa window into the liquid reservoir 128 that allows a user to visuallymonitor the liquid level.

In one embodiment, the generated hydrogen passes through the check valve130. The check valve 130 allows hydrogen to exit the cartridge 106, butprevents hydrogen from returning into the cartridge 106. The check valve130 also prevents hydrogen from exiting the system 100 when thecartridge 106 has been removed. This conserves hydrogen, provides asafety check for the user, and allows an amount of hydrogen to be storedin the system 100 for later use. The check valve 130 is in inline fluidcommunication with the hydrogen ports 114. In one embodiment, a secondcheck valve is integrated into the lid of the cartridge receiver 105, orinto a receiver gas port in the cartridge receiver 105. The check valve130 may be a silicone duckbill type valve, or a diaphragm type valvesupplied by United States Plastics of Lima, Ohio.

In one embodiment, a hydrogen pressure sensor 132 downstream from thecheck valve 130 measures the gas pressure of the hydrogen. In a furtherembodiment, the hydrogen pressure sensor 132 measures the hydrogenpressure in the system upstream of the hydrogen regulator 142. Thehydrogen pressure sensor 132 may be used for safety purposes and/or tomonitor hydrogen generation rates. In one embodiment, controller 192 ofthe electrical and control system 103 may use the pressure valuesmeasured by the hydrogen pressure sensor 132 to determine a pump pulserate for the pump 126 using a pressure curve, as described above. Ingeneral, the controller 192 may increase the pulse rate for low pressuremeasurements, and decrease the pulse rate for high pressuremeasurements. More curves, such as power demand or other curves, mayalso be factored into determining an optimal pulse rate. Monitoring thepressure using the pressure sensor 132 also allows the system 100 toadjust the pressure before it reaches unsafe levels. If pressure isabove a predetermined safety value, the electrical and control system103 may vent hydrogen out through the hydrogen purge valve 166 to returnthe system to a safe pressure.

In one embodiment, the mechanical valve 133 is positioned upstream ofthe hydrogen pressure regulator 142. In one embodiment, the mechanicalvalve 133 is a mechanical valve configured to automatically release gaspressure when the pressure is greater than a predetermined pressure. Inone embodiment, the predetermined pressure associated with themechanical valve 133 is higher than the predetermined safety valueassociated with the hydrogen pressure sensor 132 described above. In oneembodiment, the predetermined pressure associated with the mechanicalvalve 133 is about 24 pounds per square inch gauged (psig), and thepredetermined safety value associated with the hydrogen pressure sensor132 is between about 25 to 30 psig or higher depending on system designrequirements, such as 100 psig.

In one embodiment, one or more other system components are configured torelease hydrogen pressure in the event that the hydrogen pressureregulator 142 fails. The other system components may include O-rings,hose fittings or joints, the pump 126, or other mechanical components orconnections. The multiple levels of pressure release provides addedsafety to the user, and ensures that the system 100 remains at a safepressure, with no danger of explosions or other damage to the system 100or to the user. Low pressure systems are not only safer than higherpressure systems, but in general they have lower material andconstruction costs.

In one embodiment, the hydrogen passes through a water trap 134. Thewater trap 134 is configured to remove moisture from the hydrogen gas.In a further embodiment, the water trap 134 also comprises one or moreparticulate filters configured to filter particles from the hydrogengas. The particulate filters may be substantially similar to theparticulate filter described above. Filtering the hydrogen reducescorrosion, wear, and other damage that may be done to the fuel cellstack 158, and extends the life of the system 100. In one embodiment,the moisture removed from the water trap 134 passes through transfervalve 136 to the liquid reservoir 128. The recycled water can then beinjected into the hydrogen fuel cartridge 106 as described above.

In one embodiment, the liquid reservoir 128 has a condenser 138. Thecondenser 138 removes water from air and other gasses that enter theliquid reservoir 128. In one embodiment, water condenses on frit orother material in the condenser. In a further embodiment, the air andother gasses exit the system through the pressure control valve 140after passing through the condenser 138.

In one embodiment, the hydrogen passes from the water trap 134 to ahydrogen consuming device 102, such as a hydrogen fuel cell system. Infurther embodiments, the hydrogen consuming device 102 may comprise amicroturbine system or other hydrogen combustion system, a hydrogenstorage tank, or another device that consumes, stores, or otherwise useshydrogen. In one embodiment the hydrogen consuming device 102 maycomprise a hydrogen pressure regulator 142, a hydrogen pressure sensor144, a hydrogen fuel cell stack assembly 146, one or more air filters150, one or more air pumps 152, an air humidifier 156, a modular stack158, a hydrogen humidifier 160, one or more cooling fans 162, atemperature sensor 164, a hydrogen purge valve 166, and one or morepower storage devices 168.

In one embodiment, the hydrogen regulator 142 regulates the flow ofhydrogen into the hydrogen fuel cell stack assembly 146 from the watertrap 134. The hydrogen regulator 142 may cooperate with the check valve130 to store hydrogen between the check valve 130 and the hydrogenregulator 142, even between uses of the system 100. The hydrogenregulator 142 releases a controlled amount of hydrogen into the fuelcell stack assembly 146, maintaining a predetermined gas pressure in thefuel cell 146. In one embodiment, the predetermined gas pressure in thefuel cell 146 is about 7 psi. In a further embodiment, the system 100may comprise one or more hydrogen output regulators to control theamount of hydrogen gas that the hydrogen generation system 101 releases.The one or more hydrogen output regulators may comprise the check valve130, the hydrogen regulator 142, and/or the controller 192, as describedabove.

In one embodiment, the hydrogen pressure sensor 144 measures the gaspressure of the hydrogen in the system 100 downstream of the hydrogenregulator 142. (i.e. within the hydrogen consuming device 102). Thehydrogen pressure sensor 144 may be used for safety purposes, and/or tomonitor hydrogen use by the fuel cell 146. If pressure is above apredetermined safety value, hydrogen may be vented from the systemthrough the hydrogen purge valve 166 to return the pressure to a safelevel. In one embodiment, if the pressure is below the predeterminedfuel cell gas pressure described above, the hydrogen regulator 142releases more hydrogen into the fuel cell stack 146.

The hydrogen fuel cell stack assembly 146 creates electric power from aflow of hydrogen and an oxygen source such as air, as is known in theart. In general, each fuel cell 158 in the hydrogen fuel cell stackassembly 146 has a proton exchange membrane (PEM), an anode, a cathode,and a catalyst. A micro-layer of the catalyst is usually coated ontocarbon paper, cloth, or another gas diffusion layer, and positionedadjacent to the PEM, on both sides. The anode, the negative post of thefuel cell 158, is positioned to one side of the catalyst and PEM, andthe cathode, the positive post of the fuel cell, is positioned to theother side. The hydrogen is pumped through channels in the anode, andoxygen, usually in the form of ambient air, is pumped through channelsin the cathode. The catalyst facilitates a reaction causing the hydrogengas to split into two H+ ions and two electrons. The electrons areconducted through the anode to the external circuit, and back from theexternal circuit to the cathode. The catalyst also facilitates areaction causing the oxygen molecules in the air to split into twooxygen ions, each having a negative charge. This negative charge drawsthe H+ ions through the PEM, where two H+ ions bond with an oxygen ionand two electrons to form a water molecule.

In one embodiment, one or more air filters 150 are configured to filterair for use by the fuel cell stack assembly 146. In one embodiment, oneor more air pumps 152 draw air into the system 100 through the airfilters 150. The air pumps 152 may be diaphragm pumps, or other types ofair pumps capable of maintaining an air pressure to match the hydrogenpressure in the fuel cell, for a maximum power density in the fuel cellstack 146. In one embodiment, the air pumps 152 are configured toincrease or decrease the air flow in response to a signal from theelectrical and control system 103. The electrical and control system 103may send the activating signal in response to a determined electricalload on the system 100. Varying the air flow as a function of theelectrical load reduces parasitic power losses and improves systemperformance at power levels below the maximum. In one embodiment, theone or more air pumps 152 have multiple air pumping capabilitiesconfigured to optimize the amount of air delivered to the fuel cellstack 146. For example, a smaller capacity air pump 152 may be activatedduring a low power demand state, a larger capacity air pump 152 may beactivated during a medium power demand state, and both the smaller andthe larger capacity air pumps 152 may be activated during a high powerdemand state.

In one embodiment, the air humidifier 156 humidifies the air enteringthe fuel cell stack 146. Adding moisture to the air keeps the PEMs ineach of the fuel cells 158 moist. Partially dehydrated PEMs decrease thepower density of the fuel cell stack 146. Moisture decreases theresistance for the H+ ions passing through the PEM, increasing the powerdensity. In one embodiment, moist air exiting the fuel cell stack 146flows past one side of a membrane within the air humidifier 156 beforeexiting the fuel cell stack 146, while dry air flows past the other sideof the membrane as the dry air enters the fuel cell stack 146. Water isselectively drawn through the membrane from the wet side to the dryside, humidifying the air before it enters the fuel cell stack 158.

In one embodiment, the hydrogen humidifier 160 is configured to humidifythe hydrogen entering the fuel cell stack 146, such that the PEM remainsmoist. This is useful if the fuel cell stack 146 is being run at a veryhigh power density, or at a very high 4temperature, and the moisturealready in the hydrogen is not enough to keep the PEM moist. Thehydrogen humidifier 160 may be configured in a similar manner as the airhumidifier 156, with hydrogen flowing into the fuel cell stack 146 onone side of a membrane within the hydrogen humidifier 160, and moist airflowing out of the fuel cell stack 146 on the other side of themembrane, the membrane selectively allowing water to pass through tohumidify the hydrogen. The moist hydrogen will moisten the anode side ofthe PEMs, while the moist air from the air humidifier 156 will moistenthe cathode side of the PEMs.

In a further embodiment, the air humidifier 156 and the hydrogenhumidifier 160 may be integrated with each other and/or with the fuelcell stack 158. The air humidifier 156 and the hydrogen humidifier 160may each comprise an input gas chamber and a water vapor chamber, with awater-selective membrane disposed between them. The air humidifier 156and the hydrogen humidifier 160 may be integrated with structuralmembers of the fuel cell stack assembly 146, and may be configured tohave an area footprint less than or equal to the area footprint of oneor more of the fuel cells in the fuel cell stack 158.

In one embodiment, the one or more cooling fans 162 prevent the fuelcell stack 158 from overheating. The electrical and control system 103controls the operation and speed of the cooling fans 162. Separating thecooling system 162 from the fuel cell stack air supply system decreasesthe dehydration of the PEM since the air supply can be kept at a muchlower flow than is required for cooling. A fuel cell system withseparated cooling and air supply systems are referred to as closedcathode systems. In one embodiment, the cooling fans 162 are low powerfans that provide high airflows. In a further embodiment, the airflowfrom the cooling fans 162 may be adjusted according to the temperatureof the fuel cell stack 158 to reduce parasitic power losses. In anotherembodiment, the one or more cooling fans 162 comprise one or moreblowers configured to maintain a higher air pressure than an axial fan.One or more forms, guides, ducts, baffles, manifolds, or heat dams maybe used to control and direct the flow of air, or to maintain apredefined air pressure in and around the fuel cell stack 146.

In one embodiment, the temperature sensor 164 measures the temperatureof the fuel cell stack 162. As described above, in one embodiment thecooling fans 162 may be activated based at least in part on thetemperature that the temperature sensor 164 measures. In a furtherembodiment, the electrical and control system 103 is configured toshutdown the system 100 and to notify the user if the temperature sensor164 measures a temperature higher than a predetermined unsafetemperature value.

In one embodiment, a hydrogen purge valve 166 is coupled to the fuelcell stack 146. The hydrogen purge valve 166 vents hydrogen from thefuel cell stack 146. The hydrogen purge valve 166 may be used to venthydrogen when pressures reach unsafe levels, as measured by the hydrogenpressure sensors 132, 144 described above, or routinely to keep the fuelcells 158 in good condition by removing accumulated liquid water andimpurities from the fuel cell stack 158, improving performance, andpreventing corrosion of the catalyst over time. The electrical andcontrol system 103 may send a purge signal to the hydrogen purge valve166 when the pressure reaches an unsafe level, or when the electricalpower produced by the fuel cell stack 146 is below a predefined level.In one embodiment, the hydrogen exiting the fuel cell stack 158 throughthe hydrogen purge valve 166 and the moist air that has exited the fuelcell stack 158 are sent to the liquid reservoir 128 and passed throughthe condenser 138 to recycle the water formed in the reaction in thefuel cell stack 146 for reuse.

In one embodiment, one or more power storage devices 168 are coupledelectrically to the fuel cell stack 146. In one embodiment, the powerstorage devices 168 are rechargeable, and are trickle-charged by thefuel cell stack 146 when it is not in use or after the load has beendisconnected to use up excess hydrogen produced by the system 100 duringshutdown. The power storage devices 168 provide instantaneous power tothe load during a startup phase for the system 100. This means that aload connected to the system 100 will have instantaneous power, and willnot have to wait for the hydrogen generation system 101 to begingenerating hydrogen, or for the fuel cell stack 146 to begin producingelectricity before receiving power.

In one embodiment, the power storage devices 168 are configured to heatthe fuel cell stack 146 in cold environments to allow rapid startup ofthe fuel cell stack 146. The power storage devices 168 may heat the fuelcell stack 146 using a heating coil or other heated wire, or by usinganother electric heating method. In one embodiment, the power storagedevice 168 is coupled to the fuel cell stack 146 in parallel, and actsto level the load on the fuel cell stack 146 so that the fuel cell stack146 can operate at its most efficient power level without constantlyvarying its output based on the load. The power storage devices 168 willsupplement the power generated by the fuel cell stack 146 during a spikein the electrical power drawn by the load.

The power storage devices 168 may be selected from a group consisting ofbatteries, such as sealed lead acid batteries, lithium ion (Li-ion)batteries, nickel metal hydride (NiMH) batteries, or a variety ofrechargeable batteries, a capacitor, a super capacitor, and otherdevices capable of storing electric power. In one embodiment, powerstorage devices 168 are selected for use with power capacities that maybe larger than are necessary to supplement the fuel cell stack 146 inorder to avoid deep cycling of the power storage devices 168 and toincrease the life of the power storage devices 168. In one embodiment,the power storage devices 168 comprise a capacitor coupled directly tothe fuel cell stack 146 in a parallel configuration, and a battery orother power storage device coupled indirectly to the fuel cell stack 146in parallel after a direct current (DC) to DC converter 172 or otherelectrical device.

In one embodiment, the electrical and control system 103 is coupled forelectrical power and control signal communication with the sensors,valves, and other components of the system 100. In one embodiment, theelectrical and control system 103 includes one or more voltage andcurrent sensors 170, a DC to DC converter 172, a circuit breaker 174, aground fault circuit interrupter (GFCI) device 176, an electronic switch178, a DC outlet 180, an alternating current (AC) inverter 181, an ACoutlet 182, a circuit breaker switch 184, a GFCI switch 186, a display188, a keypad 190, a controller 192, a computer communication interface194, and a control bus 196.

In one embodiment, the voltage and current sensors 170 are configured tomeasure one or more of the voltages and the currents at both poles ofthe power storage device 168. The electrical and control system 103 mayuse the measured voltages and currents to determine the charge level ofthe power storage device 168. Based on the measurements of the voltageand current sensors 170, the electrical and control system 103 maydetermine whether to charge the power storage device 168 or draw on thepower storage device 168 to supplement or proxy for the fuel cell stack146. In one embodiment, the electrical and control system 103 alsoprovides the power status of the battery to the user.

In one embodiment, the DC to DC converter 172 is configured to convertthe variable voltage of the fuel cell stack 146 circuit to asubstantially constant voltage. In one embodiment, the substantiallyconstant voltage is a standard voltage, such as 5 Volts, 9 Volts, 12Volts, 14 Volts, 24 Volts and the like. In one embodiment, the DC to DCconverter 132 is a switching converter, such as a buck, boost,buck-boost, inverting, forward, flyback, push-pull, half bridge, fullbridge, Cuk, or SEPIC DC to DC converter. In a further embodiment, theDC to DC converter 132 comprises a voltage regulator. In general, use ofa switching DC to DC converter results in less power loss than a voltageregulator DC to DC converter. The DC to DC converter 172 may provideelectric power to the electrical components of the system 100 and to anelectric load that is coupled to the system 100.

In one embodiment, the circuit breaker 174 interrupts the electriccircuit in response to an electrical overload or an electrical short inthe circuit. An overload in the circuit may occur if the electric loadrequires more current than the system 100 can provide. In oneembodiment, the rating of the circuit breaker 174 is determined by theelectric power generating capabilities of the system 100. In oneembodiment, the circuit breaker 174 is a standard rated circuit breakerrated for the current level of the electrical and control system 103. Inone embodiment, the circuit breaker switch 184 is configured to resetthe circuit breaker 174 after the circuit breaker 174 interrupts thecircuit.

In one embodiment, the GFCI device 176 interrupts the electric circuitin response to an electrical leak in the circuit. The GFCI device 176can interrupt the electric circuit more quickly than the circuit breaker174. The GFCI device 176 is configured to detect a difference in theamount of current entering the circuit and the amount of current exitingthe circuit, indicating an electrical current leak, or a separate pathto ground. In one embodiment, the GFCI device 176 is able to sense acurrent mismatch as small as 4 or 5 milliamps, and can react as quicklyas one-thirtieth of a second to the current mismatch. In one embodiment,the GFCI switch 186 is configured to reset the GFCI device 176 after theGFCI device 176 interrupts the circuit.

In one embodiment, electronic switch 178 disconnects the load fromelectric power, without disconnecting the rest of the circuit. In oneembodiment, the electronic switch 178 disconnects the load after a userinitiated a power down phase of the system. During a shutdown state, thesystem 100 may activate the electronic switch 178 and disconnect theload continue to generate electricity to charge the power storage device168 and to use excess hydrogen.

In one embodiment, the DC outlet 180 provides an outlet or pluginterface for supplying DC power to DC devices. In one embodiment, theDC power has a standard DC voltage. In one embodiment, the standard DCvoltage is about 9 to 15 Volts DC. In a further embodiment, the DCoutlet 180 is a “cigarette lighter” type plug, similar to the DC outletsfound in many automobiles.

In one embodiment, the AC inverter 181 converts DC power from the DC toDC converter 176 to AC power. In one embodiment, the AC inverter 181converts the DC power to AC power having a standard AC voltage. Thestandard AC voltage may be chosen based on region, or the intended useof the system 100. In one embodiment, the standard AC voltage is about110 to 120 Volts. In another embodiment, the standard AC voltage isabout 220 to 240 Volts. In one embodiment, the AC inverter 181 convertsthe DC power to AC u E; g power having a standard frequency, such as 50Hz or 60 Hz. The standard frequency may also be selected based onregion, or by intended use, such as 16.7 Hz or 400 Hz.

In one embodiment, the AC outlet 182 provides an outlet or pluginterface for supplying AC power from the AC inverter 181 to AC devices.In one embodiment, the AC outlet 182 is configured as a standard ACoutlet according to a geographical region.

In one embodiment, the display 188 is configured to communicateinformation to a user. The display 188 may be a liquid crystal display(LCD), a light emitting diode (LED) display, a cathode ray tube (CRT)display, or another display means capable of signaling a user. In oneembodiment, the display 188 is configured to communicate error messagesto a user. In a further embodiment, the display 188 is configured tocommunicate the amount of power stored by the power storage device 168to a user. In another embodiment, the display 188 is configured tocommunicate the usage status of the hydrogen fuel cartridge 106 to auser.

In one embodiment, the keypad 190 is configured to receive input from auser. In one embodiment, the user is a technician, and the keypad 190 isconfigured to facilitate system error diagnosis or troubleshooting bythe technician. The input may be configured to signal the system 100 tobegin a start up or shut down phase, to navigate messages, options, ormenus displayed on the display 188, to signal the selection of a menuitem by the user, or to communicate error, troubleshooting, or otherinformation to the system 100. The keypad 190 may comprise one or morekeys, numeric keypad, buttons, click-wheels, or the like.

In one embodiment, the controller 192 is configured to control one ormore components of the system 100. The controller 192 may be anintegrated circuit such as a micro-processor, an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA), anembedded controller, or the like and related control circuitry. Thecontroller 192 communicates with the hydrogen pressure sensor 132, thetemperature sensor 118, the RFID sensor 124, the optical sensor 120, thepump 126, the level detector 129, the air pump 152, the hydrogenpressure sensor 144, the electrical sensors 170, the temperature sensor164, the display 188, the keypad 190, and/or other components.

In one embodiment, the controller 192 uses a control bus 196 tocommunicate with the components. The control bus may be one or morewires, or another communications medium providing control commands anddata in series or parallel. The controller 192 may communicate on thebus using digital or analog communications. The controller 192 maymonitor and optimize system efficiency and system safety, as discussedabove. In one embodiment, the control bus 196 may comprise a serialperipheral interface (SPI) bus.

In one embodiment, the controller 192 balances the supply of electricpower delivered to the electric load between the electric powergenerated by the fuel cell stack 158 and the electric power stored bythe electric power storage devices 168. The controller 192 may balancethe supply of electric power based on the communication signals that thecontroller 192 receives on the control bus 196, as described above, theelectric power demands of an electric load, and/or one or moremathematical or statistical curves. In one embodiment, the controller192 actively monitors the electric state of the power storage devices168, the fuel cell stack 158, and the electric power demands of theelectric load. The controller 192 may increase the electric power outputof the power storage devices 168 in response to an electric power demandby the electric load that is higher than the electric power output ofthe fuel cell stack 158, and may charge the power storage devices 168with excess power from the from the fuel cell stack 158 in response toan electric power demand by the electric load that is lower than theelectric power output of the fuel cell stack. As described above withregards to the power storage devices 168, this increases the efficiencyof the system 100, decreases wasted electric power, and provides abuffer for the fuel cell stack 158 such that the fuel cell stack 158does not constantly vary its output based on the demands of the electricload.

The controller 192 may balance the supply of electric power actively orpassively. For example, the fuel cell stack 158 and the power storagedevices 168 may be electrically coupled in a parallel configuration,such that the controller 192 passively balances the electric powerdelivered to the electric load between them. The controller 192 maybalance the electric power by draining the power storage devices 168under high loads and during hydrogen production delays, and charging thepower storage devices 168 under low loads.

In another embodiment, the controller 192 may use device switching tobalance the electric power delivered to the electric load based on thecommunication signals that the controller 192 receives on the controlbus 196. The controller 192 may balance the electric power by sendingcontrol signals to one or more switches coupled electrically to thesubsystems described above, such as the cartridge cooling system 112,the one or more liquid pumps 126, the one or more air pumps 152, thefuel cell cooling system 162, and the like. For example, the controller192 may adjust the output of the air pumps 152 to increase or decreaseelectrical output of the fuel cell stack 158, in response to anincreased electric power demands, or safety reasons such as atemperature reading from the fuel cell temperature sensor 164. In oneembodiment, the control signals are pulse width modulated (PWM) signals,and the switches are PWM controlled metal oxide semiconductor fieldeffect transistors (MOSFETs). In addition to balancing the electricpower output between the fuel cell stack 158 and the one or more powerstorage devices 168, the controller 192 may increase or decreasehydrogen output by the hydrogen generation system 101 by calculating aliquid injection rate based on the power demands of the electric load orbased on a hydrogen pressure reading by the hydrogen pressure sensor132, as described above with regards to the one or more liquid pumps126.

In one embodiment, the controller 192 may store one or more systemstatus messages, performance data, or statistics in a log that may beaccessed by a user using the display 190 or the computer communicationinterface 194. In one embodiment, the controller 192 and other circuitryare positioned to prevent shorts and fire due to water within the outerhousing 104. For example, in one embodiment, the controller 192 andother circuitry are position towards the top of the system 100.

In one embodiment, the computer communication interface 194 isconfigured to interface the controller 192 with a computer. The computercommunication interface 194 may comprise one or more ports, terminals,adapters, sockets, or plugs, such as a serial port, an Ethernet port, auniversal serial bus (USB) port, or other communication port. In oneembodiment, a computer may use the computer communication interface 194to access system logs, performance data, system status, to change systemsettings, or to program the controller 192.

In one embodiment, the outer housing 104 is configured to enclose andprotect the system 100. The outer housing 104 comprises a durablematerial such as metal, plastic, and the like. In one embodiment, theouter housing 104 is a lightweight material to increase the portabilityof the system 100. In a further embodiment, the outer housing 104 has ahole or a window to facilitate monitoring of the liquid level in theliquid reservoir 128 by the user. In a further embodiment, the housing104 is further configured to provide electronic frequency shielding tocomponents of the electric and control system 103.

FIGS. 2A and 2B illustrate embodiments of a hydrogen fuel cartridge 200that is substantially similar to the hydrogen fuel cartridge 106 ofFIG. 1. The fuel cartridge 200 a,ba,b may include a tubular body orhousing 202 a,b. In one embodiment, the housing 202 a,b is sized to beportable, and may range from about 1 to 5 inches in diameter and fromabout 4 to 12 inches in length. In a further embodiment, the housing 202a,b is much larger, and is configured for installation in a building,vehicle, or other non-portable application. The housing 202 a,b is notlimited to any particular cross-sectional shape or any particulardimensions, but may have a circular cross-sectional shape.

In one embodiment, the housing 202 a,b is formed of a material such asaluminum which has sufficient strength, is comparatively light, and hasgood heat transfer characteristics. However, many substitute materialswill be readily apparent to those skilled in the art, including steel,stainless steel, copper, carbon fiber epoxy composites, fiberglass epoxycomposites, PEEK, polysulfone derivatives, polypropylene, PVC, or othersuitable materials. In one embodiment, the fuel cartridge 200 a,b alsohas a top end cap 204 a,b allowing the fuel cartridge 200 a,b to beeasily positioned and locked into place with other components of theoverall hydrogen generation system 100 as described above.

In one embodiment, the top end cap 204 a,b comprises an alignmentstructure 208 a,b, one or more hydrogen ports 212 a,b, and one or morewater ports 216 a,b. In one embodiment, the hydrogen ports 212 a,b andthe water ports 216 a,b may also comprise one or more self sealingdevices know to the art. The alignment structure 208 a,b or otherlocking feature is configured to ensure that the top end cap 204 a,b canonly engage the cartridge receiver 105 in one orientation. In oneembodiment, the housing 202 a,b includes a crimp 224 a,b, substantiallycircumscribing the housing 202 a,b near the open end of the housing 202a,b. The crimp 224 a,b secures the housing 202 a,b to the top end cap204 a,b. In addition, the crimp 224 a,b is configured to releaseinternal hydrogen gas and water in response to a dangerously high gaspressure build up within the housing 202 a,b. In further embodiments,other securing methods such as threading, glue or other adhesives,welding, or the like may secure the top end cap 204 a,b to the housing202 a,b.

In one embodiment, the one or more hydrogen ports 212 a,b and the one ormore water ports 216 a,b are substantially similar to the one or morehydrogen ports 114 and the one or more water ports 111 described above.In one embodiment, the hydrogen ports 212 a,b and the water ports 216a,b are about one sixteenth of an inch. In one embodiment, one or morefluid injection tubes 218 a,b extend into the interior of the cartridgereceiver 202 a,b which holds a solid reactant (as explained in moredetail below) from the one or more water ports 216 a,b. In oneembodiment, the injection tubes 218 a,b may extend into the housing 202a,b at least half of the length of the housing 202 a,b, in otherembodiments the injection tubes 218 a,b may extend less than half thehousing's length. In one embodiment, the water injection tubes 218 a,bhave an inside diameter of about 1 mm. In a further embodiment, thewater injection tubes 218 a,b have an inside diameter ranging from about0.5 to 5.0 mm.

The injection tubes 218 a,b may be made of aluminum, brass, or othermetal, PTFE, Nylon®, or other high temperature polymers. In oneembodiment, a series of liquid distribution apertures will be formedalong the length of the water injection tubes 218 a,b. In anotherembodiment, the cartridge 200 a,b is oriented vertically, and theinjection tubes 218 a,b are configured to extend substantially to thebase of the cartridge 200 a,b, such that water successively fills thecartridge 200 a,b from the base towards the top end cap 204 a,b. In thismanner the water may also be pumped out of the cartridge 200 a,b throughthe injection tubes 218 a,b to further control hydrogen production andto maintain a safe hydrogen pressure.

FIG. 3A illustrates a further embodiment of a fuel cartridge 300. Asdescribed above, in one embodiment, the fuel cartridge 300 comprises asolid reactant such as a solid anhydrous chemical hydride. In oneembodiment, a chemical hydride may be considered a reducing compoundcontaining a metal and hydrogen that generates hydrogen gas when itreacts with water or other oxidizing agents.

In one embodiment of the present invention, the chemical hydridereactant utilized in the fuel cartridge 300 may be a dry, powdered formof sodium borohydride (NaBH₄) mixed with a dry activating agent. TheNaBH₄ is particularly suitable for use in the pouch 302 seen in FIG. 3Band in one embodiment, the NaBH₄ will have a grain size ranging fromabout mesh 10 to about mesh 1000. In a preferred embodiment, theactivating agent is an anhydrous, powdered solid when mixed with NaBH₄,since solids tend to react very slowly with each other. However, inalternative embodiments, the activating agent could also be mixed intoan organic/oil solvent. In addition, the activating agent in certainembodiments is preferably water soluble to increase its effectiveness,since the greater its solubility, the greater its potential to activatethe water/NaBH₄ reaction.

One effective activating material is magnesium chloride (MgCl₂), sinceit is relatively lightweight, low cost, and strongly activating. Otherpotential activating agents are other salts of Group IIA (alkaline earthmetals), or Group IIIA with Group VIIA (halides), such as AlCl₃,BeF₂,BeCl₂, BeBr₂, BeI₂, MgF₂, MgBr₂, Mg₂I, CaF₂, CaCl₂, CaBr₂, and CaI₂. Thefluorides and chlorides are preferred because they have a lowermolecular weight. However, some of these salts may be less preferreddepending on their degree of solubility in water or if they areconsidered toxic (e.g., beryllium compounds).

Activating agents may also include other water soluble salts such asGroup IA (alkali metals) salts including LiF, LiCl, LiBr, LiI, NaF,NaCl, NaBr, NaI, KF, KCl, KBr, and KI. Group IA and Group IIA hydroxidesmay be less preferred, since they make basic solutions in water and thusreduce the reaction rate. Group IA and Group IIA oxides may also be lesspreferred since they tend to be more stable and thus not as reactive.However, Group IA and Group IIA sulfides, sulfates, and selenides, suchas Li₂S, Li₂Se, Mg(SO₄)₂ may be better activating agents if they aresufficiently water soluble. In one preferred embodiment, the activatingagents will be from the group of MgCl₂, BeCl₂, LiCl, NaCl, or KCl.However, any of the above activating agents may be employed given theproper design and use conditions. In certain embodiments, the activatingagent will have a grain size ranging from about mesh 10 to about mesh1000.

In one preferred embodiment, the quantity of activating agent mixed withthe chemical hydride will be from about 10 weight percent to about 65weight percent and more preferably about 50 weight percent to about 60weight percent. In one embodiment, the quantity of activating agent is55 weight percent. In the embodiment where the solid reactant is 55weight percent MgCl₂, approximately 0.8 gm of water will be required tofully react each gm of solid reactant. One consideration in optimizingthe amount of activating agent is determining the minimum amount of thematerial which gives the desired hydrogen generation rate and results incomplete reaction/utilization of the NaBH₄. For a 55 weight %MgCl₂/NaBH₄ mixture, the energy density is 3116 Whr/kg. For comparison,the energy density of a 20 weight % NaBH₄/H₂O mixture (i.e., NaBH₄dissolved in water) is 1066 Whr/kg, while the energy density for NaBH₄alone is 7101 Whr/kg.

An alternative activating agent maybe an anhydrous or powdered acid suchas boric acid (H₃BO₃), oxalic acid, tartaric acid, citric acid, etc.Such anhydrous acids can be mixed with the NaBH₄ without reaction, butwhen water is added, the anhydrous acid dissolves and thus causes areaction. Weak or relatively insoluble anhydrous acids such as boricacid when mixed with NaBH₄ produce hydrogen in the presence of water ata relatively low rate, and thus are less preferred. Strong acids such asoxalic acid are very soluble in water and generate substantial hydrogenwhen mixed with NaBH₄. However, this mixture is difficult to control andis also less preferred. However, intermediate strength acids, such astartaric acid or citric acid are more favorable. In one preferredembodiment, the strength (Ka) of the dry acid will range from about1×10⁻⁴ to about 1×10⁻¹¹. In certain embodiments, the powdered acid willhave a grain size ranging from about mesh 10 to about mesh 1000. In onepreferred embodiment, the quantity of tartaric acid mixed with NaBH₄will be from about 5 to about 50 weight percent and more preferablyabout 8 to about 12 weight percent. In this embodiment, approximately0.8 gm of water will be required to fully react each gram of solidreactant.

As a further alternative, an inexpensive, water-insoluble catalyst maybe mixed with the NaBH₄. The catalyst can act to accelerate thewater/NaBH₄ reaction as water is injected. Such metal catalyst couldinclude Co, Ni, Cu, Pt, Pd, Fe, Ru, Mn, and Cr. Typically, the metalcatalyst will be in a powder form (e.g., particles less than 25 um) andwill be added to the chemical hydride in an amount of about 25 weightpercent to about 65 weight percent. In this embodiment, approximately0.8 gm of water will be required to fully react each gram of solidreactant.

A still further alternative to mixing an anhydrous activating agent withthe NaBH₄ may be to mix the water soluble activating agent in with thewater before it is injected into the cartridge containing anhydrousNaBH₄ or other metal hydride. This has the advantage that an aqueoussubstance such as hydrochloric acid (HCl) may be used as the liquiddescribed above. In this embodiment, the activating material is held inseparate container or liquid reservoir such as the liquid reservoir 128of FIG. 1. This container may be attached to the cartridge housing 300,or could be detached in other embodiments.

Although NaBH₄ is mainly discussed above, alternative chemical hydridesmay include (but are not limited to) lithium borohydride, lithiumaluminum hydride, lithium hydride, sodium hydride, and calcium hydride.In certain embodiments, these latter chemical hydrides need not becombined with a powdered activating agent as described above and may beactivated with water alone.

In one embodiment, the chemical hydride reactant is enclosed within aliquid permeable material, or fabric pouch 302. As used herein, “fabric”includes not only textile materials, but also includes paper basedporous materials that may be used for filtration purposes. Oneembodiment of the fabric comprises a porous material which can maintainstructural integrity at temperatures ranging from about −20° C. to about200° C., and a pH ranging from about 4 to about 14.

Suitable fabrics may include but are not limited to woven or nonwovenNylon, Rayon, polyester, porous filter paper, or blends of thesematerials. In one embodiment, the material for the pouch 302 may beselected for optimal thickness, density, and water retention. In oneembodiment, the cartridge 300 is in a vertical configuration and thepouch 302 comprises a material with minimal water retention, such thatthe weight of the water retained is less than about 10 times the weightof the material itself. The material also includes little or no wickingcapabilities. In a further embodiment, the cartridge 300 is in ahorizontal configuration and a material 302 is selected with a greaterwater retention ability and some wicking ability.

The water retention and wicking potential of the pouch 302 affect wherethe chemical reaction between the water and the chemical hydride occurs.Low water retention and wicking potential helps keep the chemicalreaction at or below the water fill level in the cartridge 300. If thewater retention and wicking potential are higher, the pouch 302 wicksand retains the water such that the chemical reaction can occur abovethe fill level of the cartridge 300. Selection of a material for thepouch 302 may be based on the configuration of the cartridge 300, theinjection tubes 304, and the chemical hydride and activating agent inuse, in order to more precisely control the chemical reaction within thecartridge 300.

Other relevant factors may include water permeability, porosity,chemical reactivity, and temperature stability between about 150° C. andabout 250° C. relative to the chemical hydride, activating agent, andwater injection system 304 in use. A suitable thickness for the materialfor the pouch 302 is between about 0.002 inches and 0.01 inches. Asuitable density is less than about 0.05 grams per square inch.

In one exemplary embodiment, the pouch 302 comprises Crane® 57-30, aproduct of Crane Nonwovens of Dalton, Mass. Crane® 57-30 has a thicknessof about 0.0043 inches, has a density of about 57.9 grams per squaremeter, is water permeable, has a pore size below about 0.0025 inches, ischemically resistant in basic and acidic solutions of about pH 4 toabout pH 13, is stable in temperatures up to about 180° C., and retainsonly about 4 times its own weight in water. Other combinations ofmaterial properties such as thickness, density, and water retention thatare configured for stable hydrogen generation may also be used.

In one embodiment, the fabric pouch 302 is comparatively thin having asubstantially greater area than thickness. The pouch 302 may be formedin any conventional manner. For example, viewing FIG. 3B, it can be seenhow two rectangular sheets of fabric material 314 and 316 may be sealedalong three edges (for example by stitching 310 or other sealingmethods) and segmented into 0.25 to 2 inch sections 318 (also bystitching) to leave open ends 312. The series of sections 318 thusformed are filled with a fine grain chemical hydride, as describedabove, and sealed along the fourth edge by stitching closed open ends312.

An illustrative thickness of the pouch 302 (i.e., the thickness ofsections 318 when unrolled and charged with a chemical hydride) may beapproximately ¼ of an inch in one embodiment and its unrolled dimensionscould be approximately 5.75 inches by 20 inches. Then the pouch 302 isrolled to a diameter sufficiently small to be inserted into tubularhousing 300 as suggested in FIG. 3A (the top end cap 206 has beenremoved for purposes of clarity). The thickness of the pouch 302 and theunrolled dimensions may be determined based on the size of the cartridge300, and the configuration of the pouch 302. The water injection tubes304 are then carefully inserted between overlapping layers of the rolledpouch 302. In one embodiment, a liner (not shown) is also disposedwithin the housing 300 to protect the housing 300 from corrosion anddamage. The liner may be removable or permanent, and may serve to extendthe life of the housing 300. In one embodiment, the liner is a bag orpouch consisting of a plastic or other inert material known in the art,and the liner is configured to withstand the temperatures associatedwith a hydrogen generating chemical reaction, and to protect thecartridge 300 from corrosion.

The rolled pouch 302 may be rolled such that a longitudinal axis of therolled pouch 302 is oriented coaxial with a longitudinal axis of thehousing 300, as depicted. In another embodiment, the rolled pouch 302may comprise multiple rolled pouches having varying lengths and arrangedin courses. As used herein, the term “course” refers to a row or columnof stacked rolled pouches 302 or single pouches 302. The varying lengthsfunction to offset course gaps between rolled pouches in the samecourse. Offsetting the course gaps ensures that hydrogen production willbe consistent while the pouches are being submerged during operation asthe fill level of liquid reactant rises. For example, if the course gapswere aligned, when the fill level reached the course gap, hydrogenproduction would slow until the subsequent row of stacked pouches beganto be submerged.

FIG. 4A illustrates a schematic block diagram of one embodiment of ahydrogen generation system interface 400 according to the presentinvention. The hydrogen generation system interface 400 includes a fuelcartridge 402, a cartridge interface 404, and a fuel cartridge receiver406. The hydrogen generation system interface 400 provides a fluidpathway for a flow of hydrogen generated by a hydrogen generationsystem.

The fuel cartridge 402, in one embodiment, contains a hydride fuel. Incertain embodiments, the fuel cartridge 402 is configured to house achemical hydride fuel and an activating agent, to receive water, tohouse a chemical reaction between the chemical hydride and the waterwhich produces hydrogen gas, and to release the hydrogen. In oneembodiment, the fuel cartridge 402 is cylindrical in shape. Thecylindrical shape provides structural strength to withstand the internalpressures as hydrogen is produced. The fuel cartridge 402 may comprise amaterial configured to withstand the heat and pressure of the chemicalreaction. The material may also comprise a lightweight material selectedto minimize the weight of the fuel cartridge 402, such as a lightweightmetal or metal alloy like aluminum, a plastic polymer, or other durablematerial. In another embodiment, the fuel cartridge 402 comprises astamped aluminum cylindrical cartridge.

The fuel cartridge 402, in one embodiment, passes generated hydrogen tothe cartridge interface 404. The fuel cartridge 402 may include passagesfor the transfer of generated hydrogen, such as tubes, manifolds,channels, or the like. In one embodiment, the fuel cartridge 402includes a machined channel providing fluid communication between theinterior of the fuel cartridge 402 and the cartridge interface 404. Inanother embodiment, the fuel cartridge 402 includes a formed channelproviding fluid communication between the interior of the fuel cartridge402 and the cartridge interface 404, such as in an injection moldingprocess.

The cartridge interface 404, in one embodiment, is attached to the fuelcartridge 402 and includes at least one cartridge interface gas outletport 408. In one embodiment, the cartridge interface 404 comprises anend cap, as described above with regards to the end cap 204 of FIGS. 2Aand 2B. The cartridge interface 404, in one embodiment, removablycouples the fuel cartridge 402 to the fuel cartridge receiver 406. Incertain embodiments, the cartridge interface 404 engages the fuelcartridge receiver 406 in response to the insertion of the fuelcartridge 402 in to a cavity 420 of the fuel cartridge receiver 406.Insertion and removal of the fuel cartridge 402 occurs along aninsertion path 410, the insertion path 410 represented by the dashedarrow in FIG. 4.

The cartridge interface gas outlet port 408, in one embodiment, is influid communication with the interior of the fuel cartridge 402 andprovides a fluid pathway for a flow of hydrogen gas generated within thefuel cartridge 402. The cartridge interface gas outlet port 408 isoriented with an orientation angle 411 relative to an orthogonal plane412. The orthogonal plane 412 is orthogonal to the insertion path 410.

In the illustrated embodiment, the interface gas outlet port 408 isoriented with an orientation angle 411 of about three degrees, meaningthat the interface gas outlet port 408 orientation is three degrees fromthe plane of the orthogonal plane 412. In another embodiment, theinterface gas outlet port 408 may have a different orientation angle411, such as five degrees from the plane of the orthogonal plane 412. Incertain embodiments, the interface gas outlet port 408 may have anyorientation angle 411 from zero to 90 degrees in any direction from theorthogonal plane 412. In another embodiment, the interface gas outletport 408 may have any orientation angle 411 from zero to 45 degrees inany direction from the orthogonal plane 412.

The cartridge interface 404 may comprise any material known in the artto withstand the pressures, temperatures, and stresses generated inhydrogen generation. In a further embodiment, the cartridge interface404 also comprises a lightweight material, to keep the overall weight ofthe system to a minimum for added portability. In one embodiment, thecartridge interface 404 is a lightweight metal or metal alloy such asaluminum or the like. In a further embodiment, the cartridge housing 105comprises a fiberglass material, a plastic polymer material, a ceramicmaterial, or another durable material.

In certain embodiments, the cartridge interface 404 is attached to thefuel cartridge 402. In another embodiment, the cartridge interface 404is formed as an integrated part of the fuel cartridge 402. In oneembodiment, the cartridge interface 404 and the fuel cartridge 402comprise a single structure.

The fuel cartridge receiver 406, in one embodiment, receives the fuelcartridge 402. The fuel cartridge receiver 406 may be configured tointerface with the cartridge interface 404 to receive a flow of hydrogengas. In one embodiment, the fuel cartridge receiver 406 includes abiasing member 414 and a receiver gas port 416.

The biasing member 414, in one embodiment, applies a force that acts tohold together the interface gas outlet port 408 and the receiver gasport 416. In one embodiment, the biasing member 414 compresses inresponse to the insertion of the fuel cartridge 402 into the fuelcartridge receiver 406.

The biasing member 414 may comprise a compliant material, a spring, orthe like. For example, the biasing member 414 may comprise a syntheticor natural rubber compound that compresses upon insertion of the fuelcartridge 402 into the fuel cartridge receiver 406. In another example,the biasing member 414 may comprise an interior wall of the fuelcartridge receiver 406 which elastically deforms upon insertion of thefuel cartridge 402, applying a resulting force to the fuel cartridgeinterface 404. The interior wall may be tapered.

In one embodiment, the biasing member 414 is diametrically opposed tothe receiver gas port 416. For example, the fuel cartridge 402 may havea circular cross section, and the fuel cartridge receiver 406 may have acorresponding substantially circular cross section. In this example, thebiasing member 414 and the receiver gas port 416 may be along a commondiameter of the substantially circular cross section of the fuelcartridge receiver 406.

In another embodiment, the fuel cartridge 402 and the fuel cartridgereceiver 406 may have a non-circular cross section. In this embodiment,a biasing member 414 diametrically opposed to the receiver gas port 416applies a force substantially in line with the receiver gas port 416.For example, a fuel cartridge receiver 406 with a substantially squarecross section may have a biasing member 414 on a first side of thesquare cross section and a receiver gas port 416 diametrically opposedon the opposite side of the square cross section.

Preferably, the biasing force created by the biasing member is such thata friction fit is created between the fuel cartridge receiver 406 andthe interface 406. In one embodiment, this friction fit is strong enoughto retain the fuel cartridge 402 in fuel cartridge receiver 406 when thefuel cartridge receiver 406 is jarred, bumped, or turned upside down. Incertain embodiments the facing walls 418 a, 418 b include additionalbiasing members or catches such as one or more nubs 420 andcorresponding recesses 422 on opposites sides of the facing walls 418 a,418 b.

In certain embodiments, the biasing member 414 may comprise another portin the fuel cartridge receiver 406 that corresponds to a port on thecartridge interface 404. For example, the biasing member 414 maycomprise a receiver water inlet port that allows water to flow into aninterface water inlet port. The receiver water inlet port may include acompliant element that compresses upon insertion of the fuel cartridge402, for example, a rubber O ring. The compressed compliant element maygenerate the biasing force that holds the interface gas outlet port 408to the receiver gas inlet port 416.

The receiver gas port 416, in one embodiment, receives the flow ofhydrogen gas from the interface gas outlet port 408. The receiver gasport 416 is configured to couple with the interface gas outlet port 408.In one embodiment, the receiver gas port 416 is coupled to the interfacegas outlet port 408 under a force generated by a biasing member 414, asdescribed above.

In one embodiment, the receiver gas port 416 is oriented in anorientation angle 413 relative to a plane orthogonal to the insertionpath 410 of the fuel cartridge 402. In certain embodiments, theorientation angle 413 of the receiver gas port 416 is such that thereceiver gas port 416 aligns with the interface gas outlet port 408. Incertain embodiments, the orientation angle 413 of the receiver gas port416 is substantially the same as the orientation angle 411 of theinterface gas outlet port 408. In the embodiment illustrated in FIG. 4,the receiver gas port 416 and the interface gas outlet port 408 have anorientation angle 411, 413 of between about zero and about five degrees.In another embodiment, the receiver gas port 416 may have an orientationangle 413 from zero to 90 degrees in any direction from the orthogonalplane 412. In another embodiment, the receiver gas port 416 may have anyorientation angle 413 from zero to 45 degrees in any direction from theorthogonal plane 412.

In certain embodiments, the interface gas outlet port 408 sweeps acrossthe receiver gas port 416 as the fuel cartridge 402 is inserted alongthe insertion path 410 into the fuel cartridge receiver 406. In otherwords, the interface gas outlet port 408 and the receiver gas port 416are configured to interfere with each other and slide against each otheras the fuel cartridge 402 is inserted into the fuel cartridge receiver406. As the interface gas outlet port 408 sweeps across the receiver gasport 416, contaminants disposed on the interface gas outlet port 408and/or the receiver gas port 416 are dislodged from the interface gasoutlet port 408 and/or the receiver gas port 416, providing aself-cleaning interface between interface gas outlet port 408 and thereceiver gas port 416.

For example, the interface gas outlet port 408 and the receiver gas port416 may have orientation angles of about three degrees. In this example,the interface gas outlet port 408 and/or the receiver gas port 416 maysweep across one another as the fuel cartridge 402 is inserted into thefuel cartridge receiver 406. Contaminants such as dirt particlesdisposed on the interface gas outlet port 408 and/or the receiver gasport 416 that protrude beyond the interface gas outlet port 408 and/orthe receiver gas port 416 will be perturbed by the sweeping action, andwill be dislodged.

FIG. 4B illustrates a schematic block diagram of an alternate embodimentof a hydrogen generation system interface 422 according to the presentinvention. The hydrogen generation system interface 422 includes a fuelcartridge 402, a cartridge interface 404, and a fuel cartridge receiver406. The hydrogen generation system interface 400 provides a fluidpathway for a flow of hydrogen generated by a hydrogen generationsystem. The fuel cartridge 402, cartridge interface 404, and fuelcartridge receiver 406 are preferably configured in a like manner tosimilarly numbered components described in relation to FIG. 4A.

The cartridge interface 404, in one embodiment, includes a shoulder 424.The shoulder 424 may be configured to align the fuel cartridge 402relative to the fuel cartridge receiver 406. In one embodiment, theshoulder 406 interferes with the fuel cartridge receiver 406 when thefuel cartridge 402 is inserted to the proper depth.

In one embodiment, the fuel cartridge receiver 406 comprises a surface426 through which the fuel cartridge 402 is inserted. The surface 426may interact with the shoulder 424 to align the cartridge interface 404in the fuel cartridge receiver 406.

Beneficially, a fuel cartridge receiver 406 comprising a surface throughwhich the fuel cartridge 402 is inserted allows the use of differinglengths of fuel cartridge 402 in the same fuel cartridge receiver 406.Since the shoulder 424 aligns the cartridge interface 404 in the fuelcartridge receiver 406 independent of the length of the fuel cartridge402, fuel cartridges of varying lengths may be employed.

FIG. 5 illustrates a schematic block diagram of one embodiment of acooling system 500 in a hydrogen generation system according to thepresent invention. The cooling system 500 may be substantially similarto the cooling module 112 of FIG. 1. In one embodiment, the coolingsystem 500 may comprise a blower 502, a shroud 504, and one or more ribs506. The cooling system 500 cools a fuel cartridge 402 in a hydrogengeneration system.

The blower 502, in one embodiment, blows air that travels through theother components of the cooling system 500. The air absorbs heat fromthe fuel cartridge 402 through conduction and carries the heat out ofthe hydrogen generation system. In an alternate embodiment, the blower502 moves an alternative cooling fluid, such as water, through thehydrogen generation system.

The shroud 504, in one embodiment, contains the air blown by the blower502 as the air passes across the surface of the fuel cartridge. In oneembodiment, the shroud 504 is disposed within or below the fuelcartridge receiver 406 and substantially surrounds the fuel cartridge402 upon insertion. The shroud 504 may be made from any material thatdirects a flow of air, but is preferably made from a light, rigidmaterial, such as a plastic.

In one embodiment, the blower 502 blows air in near a bottom 508 of theshroud 502. In the depicted embodiment, air flows from the bottom of thefuel cartridge 402 to the top of the fuel cartridge as the air absorbsheat.

In one embodiment, the one or more ribs 506 channel the flow of air. Incertain embodiments, the one or more ribs 506 comprise a single helicalrib that causes the flow of air from the blower 502 to travel in ahelical path around the fuel cartridge. Beneficially, such a helicalpath increases a dwell time that the air is in contact with the surfaceof the fuel cartridge. Those of skill in the art will recognize that thevertical spacing between ribs 506 is directly proportional to the dwelltime. The closer the ribs 506 are spaced vertically, the tighter thehelical curves and the higher the dwell time, so long as the blowerspeed is reduced to compensate for increased air speed due to a smallerhelical air channel around the fuel cartridge 402. Alternatively, theribs 506 may have other configurations which increase the dwell time ofthe cooling air.

The ribs 506, in one embodiment, induce turbulence in the flow of airfrom the blower 502. The ribs 506 may induce turbulence through anymethod known in the art, such as by being formed at an angle to a flowof air, by including ridges or undulations, by adding protrusionsseparate from the ribs 506, or in a like manner. Those of skill in theart will recognize that turbulence induced in the flow of air from theblower improves the transfer of heat from the fuel cartridge 402 to theflow of air.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. An apparatus to generate hydrogen, the apparatus comprising: a liquidpermeable material comprising one or more cavities, each cavityconfigured to at least partially enclose a solid anhydrous chemicalhydride and an anhydrous activating agent, each cavity comprising liquidpermeable material configured to permit passage of a liquid from oneside of the liquid permeable material to the other side; a housingcomprising a heat and pressure resistant material, the housingconfigured to receive the liquid permeable material, and a liquid; oneor more liquid sources configured to introduce the liquid into thehousing such that the liquid contacts at least a portion of the liquidpermeable material; and a gas outlet port configured to release hydrogengas produced by a reaction comprising the solid anhydrous chemicalhydride, the anhydrous activating agent, and the liquid.
 2. Theapparatus of claim 1, further comprising a hydrogen output regulatorconfigured to control the amount of hydrogen gas that the gas outletport releases, wherein the hydrogen output regulator comprises a checkvalve that allows the hydrogen gas to exit the gas outlet port, butsubstantially prevents the hydrogen gas from entering the gas outletport.
 3. The apparatus of claim 2, wherein the hydrogen output regulatoris further configured to regulate a gas pressure of the hydrogen gasthat the gas outlet port releases such that the gas pressure remains ator below a predetermined gas pressure.
 4. The apparatus of claim 2,wherein the one or more liquid sources comprise a liquid reservoir andone or more pumps, each of the one or more pumps configured to pumpliquid from the liquid reservoir into the housing at a liquid injectionrate.
 5. The apparatus of claim 4, wherein the hydrogen output regulatorcomprises a controller configured to manage the liquid injection rate.6. The apparatus of claim 5, wherein the controller determines theliquid injection rate based on one or more input signals.
 7. Theapparatus of claim 1, further comprising a liner disposed between thehousing and the liquid permeable material, the liner configured toprotect the housing from corrosion and damage.
 8. The apparatus of claim1, wherein the housing further comprises a crimp substantiallycircumscribing an end cap seated within a housing opening, the crimpconfigured to release the hydrogen gas in response to a gas pressureabove a predetermined gas pressure.
 9. The apparatus of claim 1, whereinthe housing further comprises an activated charcoal filter configured toabsorb impurities from hydrogen gas exiting the housing.
 10. Theapparatus of claim 1, further comprising one or more housing alignmentfeatures configured to ensure that the housing is disposed in apredetermined position and alignment relative to one or more receivingalignment features of an apparatus receiver.
 11. The apparatus of claim10, wherein the one or more housing alignment features comprise ahandle.
 12. The apparatus of claim 10, wherein the one or more housingalignment features engage the gas outlet port.
 13. The apparatus ofclaim 1, wherein the liquid comprises water.
 14. The apparatus of claim1, wherein the cavities comprise one or more tubular pouches in aside-by-side configuration.
 15. The apparatus of claim 14, wherein thehousing is cylindrical and wherein the one or more tubular pouches arerolled such that a longitudinal axis of the rolled one or more tubularpouches is oriented coaxial with a longitudinal axis of the housing. 16.The apparatus of claim 15, wherein the housing is configured to receivea plurality of tubular pouches having a plurality of lengths, theplurality of tubular pouches stacked and arranged in alternating coursessuch that a course gap between two stacked tubular patches does not lineup with a course gap in an adjacent course of liquid permeable pouches.17. The apparatus of claim 1, wherein the liquid sources furthercomprise one or more liquid conduits disposed within the housing. 18.The apparatus of claim 1, further comprising an O-ring substantiallycircumscribing the gas outlet port to produce a seal between the gasoutlet port and a receiver gas port, the O-ring configured to break theseal and release the hydrogen gas in response to a gas pressure above apredetermined gas pressure.
 19. An apparatus to generate hydrogen, theapparatus comprising: a water reservoir comprising liquid water; one ormore pumps in fluid communication with the water reservoir, the pumpsconfigured to pump the liquid water at a liquid injection rate; a waterpermeable pouch comprising one or more cavities, each cavity configuredto at least partially enclose a solid anhydrous chemical hydride and ananhydrous activating agent, each cavity comprising liquid permeablematerial configured to permit passage of a liquid from one side of theliquid permeable material to the other side, the anhydrous activatingagent comprising a salt having a metal selected from the groupconsisting of alkaline earth metals and alkali metals; a fuel cartridgecomprising a heat and pressure resistant material, the fuel cartridgeconfigured to receive the water permeable pouch and the liquid water; anend cap seated within an opening in the fuel cartridge, the end capcomprising one or more water injection tubes and a gas outlet port, theone or more water injection tubes in fluid communication with the one ormore pumps, the one or more water injection tubes configured tointroduce the liquid water into the fuel cartridge at the liquidinjection rate such that the liquid water contacts at least a portion ofthe water permeable pouch, and the gas outlet port configured to releasehydrogen gas produced by a reaction comprising the solid anhydrouschemical hydride, the anhydrous activating agent, and the liquid water;a hydrogen output regulator configured to control the amount of hydrogengas that the gas outlet port releases; and one or more fuel cartridgealignment features configured to ensure that the fuel cartridge isdisposed in a predetermined position and alignment relative to one ormore receiving alignment features of a cartridge receiver.